The use of magnetic media, specifically "mag stripe" media is well known. Magnetic stripes are found on the back of almost all bank credit, debit or access cards for use in accessing ATMs or transacting sales at a merchant. Similar stripes are well known on employee badges for controlling access to buildings and other facilities. This mag stripe technology is useful for transporting machine-readable information in a variety of other ways. For the aforementioned and similar applications, the information encoded on the mag stripe is generally permanent (e.g., an account number, a personal identification number or the like). The encoding of such information is typically done at a central facility, such as a bank, personnel office, etc. The information will then remain unchanged throughout the life of the item bearing the mag strip. Mag stripe reading technology is both inexpensive and plentiful. The holdback to wider use of this mag stripe technology is the encoding process.
Reading an encoded signal from a mag stripe is relatively easy. An encoded mag stripe is passed by a magnetic read head (i.e., "swiped"). In most applications, the user moves the mag stripe past the read head. This means that the instantaneous speed of the stripe past the read head is subject to significant variation in speed, not only from user to user, but during any single swipe operation as well. The mag stripe reading systems today are highly tolerant of these speed variations. Unless the speed of the stripe past the head is either too slow to induce a readable signal in the read head, or so fast that circuitry can't discern the magnetic pulses, an accurate read is usually accomplished. This happens because the spacing of the bits along the mag stripe is uniform, and timing or synchronizing signals are inherent in the encoded magnetic signal.
Writing (encoding) the magnetic signal onto the stripe is another matter. In order to provide a relatively uniform spacing of magnetic pulses along the stripe or track, the velocity of the mag stripe relative to the magnetic write head must be essentially constant. This is easily achieved in devices where either the write head or the magnetic media are moved by a motor-driven transport mechanism. Such mechanisms are both bulky and relatively expensive. If it were easier and/or cheaper to encode mag stripes, a great number of new applications for the technology would present themselves. However, the equipment to perform the magnetic encoding has heretofore been too expensive and/or bulky to make locally available for these types of application. Several applications are discussed which could benefit from mag stripe technology.
Batch "cards" often accompany lots of parts through a manufacturing site. More often than not, a printed batch number must be visually read and processed by a human at each work station where the batch of parts is to be processed.
Another area where batch-type identification is required is in warehouse operations. Here, individual parts or items are "picked" to make up an order, each order having a unique order number. Much paperwork is required to follow these orders though the warehouse and to see that the orders are properly shipped either to an outside customer or to the correct location internally. In addition, each part or item usually has a part number which must be tracked for inventory control.
In offices, batches of mail, complex documents, or other batch-type jobs are also often identified by a routing slip containing an identification number. Again, printed identification numbers must be assigned and affixed to each job. Human error may subsequently occur in reading these generally hand-written identification numbers.
Each of these types of application could greatly benefit from the available of low-cost, portable mag stripe writing technology.